The move follows news last week that Facebook removed over 360 pages and accounts from its social media network, which it said were "engaged in coordinated inauthentic behaviour".

Some of the offending pages and accounts were engaged in influencing public opinion in Estonia, it is reported.

The official reason for the beginning of proceedings given by Roskomnadzor is that the companies have not complied with Russian data protection laws, Reuters reports, particularly with regard to meeting the requirement of Russian Facebook and Twitter users' personal data being retained on servers within the Russian Federation.

Roskomnadzor in fact sent letters to both companies in December, before the Facebook account suspensions, demanding reports on their compliance with Russian data protection laws. The companies responded, but the regulatory body says it found their responses unsatisfactory. While token fines were in the offing, Roskomnadzor said it had no plans to block the social media sites at present.

Facebook last week removed pages and accounts whos admins or owners presented themselves as independent news sources or general interest pages covering diverse topics including sports, business and the weather. The accounts had focussed on several CEE countries including Latvia, Lithuania and Romania, as well as Estonia, and were generally linked to Sputnick the state-controlled Russian news agency, or its personnel, Facebook said.

Facebook has been used by Kremlin critics inside Russia

Regular topics aired included anti-NATO or EU sentiment, and protest movements within those countries, it is reported, with many of the pages being well-funded and organised.

Kremlin critics have said that Russian authorities will be able to access personal data used by the two social media giants much more easily, if its storage is confined to Russian territory.

Implied in that is that the laws will be used to quell criticism of Russia's ruling party, United Russia, amongst other organisations and persons. Opposition politician Aleksei Navalny, for instance, has an official Facebook page with close to 400,000 ''likes'' and an even greater number of followers, at the time of writing.

According to Estonian anti-fake news site Propastop, several fake social media accounts have been closed down as a result of its work, mostly linked with the #ESTexitEU hashtag and the Estoners Facebook group.

European Union countries like Estonia are subject to the binding General Data Protection Regulation (GDPR), aimed at protecting the personal data of persons based in the EU and the European Economic Area (EEA), amongst other things. Its rules also sometimes apply to organisations outside the EU which collect or process personal data from individuals within the EU zone.

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